Tempest tests to cover live-block-migration

Related to bug 1051881.

Two test cases: one to cover the live block migration on XenServer, and
the other to indicate that the machine status is left in an inconsistent
state in case a non-existing host is specified as target.
To run the live-migration tests with block migration, include:

    [compute]
    live_migration_available = true
    use_block_migration_for_live_migration = true

in your tempest.conf

To run these tests, the hypervisors must support the Storage XenMotion
feature.

Change-Id: I1e6cc903fa573ecd219a08bf4dddd9cc1f4f60df
diff --git a/etc/tempest.conf.sample b/etc/tempest.conf.sample
index 8d3f6c9..9c7868c 100644
--- a/etc/tempest.conf.sample
+++ b/etc/tempest.conf.sample
@@ -127,6 +127,13 @@
 # Connection string to the database of Compute service
 db_uri = mysql://user:pass@localhost/nova
 
+# Run live migration tests (requires 2 hosts)
+live_migration_available = false
+
+# Use block live migration (Otherwise, non-block migration will be
+# performed, which requires XenServer pools in case of using XS)
+use_block_migration_for_live_migration = false
+
 [image]
 # This section contains configuration options used when executing tests
 # against the OpenStack Images API